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Trapping carbon with rocks

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Many experts say that combating global warming will require both drastically reducing the use of fossil fuels and permanently removing billions of tons of CO2 already in the atmosphere.  Developing practical, large-scale technologies for carbon removal is a significant challenge.

There is a nearly inexhaustible supply of minerals that are capable of removing carbon dioxide from the atmosphere, but they don’t do it quickly enough to make a significant dent in the ever-growing supply in the atmosphere.  In nature, silicate minerals react with water and atmospheric CO2 to form minerals in the process called weathering.  But this chemical reaction can take hundreds or even thousands of years.

Researchers at Stanford University have developed a new process for converting slow-weathering silicates into much more reactive minerals that capture and store carbon quickly.  The new approach resembles a centuries-old technique for making cement.  They combine calcium oxide and another common mineral containing magnesium and silicate ions in a furnace.   The result are new materials that, when exposed to water, quickly trap carbon from the atmosphere.

In their experiments, the carbonation process took weeks to months to occur, thousands of times faster than natural weathering.

The idea would be to spread these materials over large land areas to remove CO2 from the air.  Meaningful use for trapping carbon would require annual production of millions of tons.  But the same kiln designs used to make cement could produce the needed materials using abundant minerals found in many places.  In fact, the required minerals are often common leftover materials – or tailings – from mining.

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Scientists discover low-cost way to trap carbon using common rocks

Photo courtesy of Renhour48 via Wikimedia.

Earth Wise is a production of WAMC Northeast Public Radio

Fighting fires with man-made wind

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Researchers at Ohio State University have developed a new portable tool that may help firefighters battle blazes more efficiently and with less risk.

Traditional firefighting methods include chemical foams – which are toxic – and the use of hydrants, which can strain water resources.  The recent fires in Southern California demonstrated the need for efficient fire suppression methods.  The new device works to suppress flames using conductive aerosols, which are small particles that can direct electricity.

The device uses vortex rings – small donut-shaped bands of air – that transform the aerosol particles into short pulses of wind that convert nearby oxygen into ozone.  This accelerated airflow generates rapid turbulence, which disrupts the natural combustion process and quickly extinguishes the target fire.

The device resembles a small bucket, attached to an arm brace.  Firefighters would aim the bucket toward the fire, and it would use bursts of compressed air to deliver aerosols in an electric arc to fight the fire.

Testing identified a coarse copper solution for the vortex ring material and simulations showed that the device would succeed in suppressing fires.  They then worked on optimizing the power and range of the device.

Depending on the size of the fire and number of firefighters, it is likely that several of the devices would be required in a real emergency.  According to the developers, the design of the vortex launcher is actually very simple and is very scalable.  The device is maneuverable in tight spaces and could be taken through doors and indoor environments.  Vortex rings can carry chemical payloads over longer distances than other methods, making firefighters safe by staying further from flames. 

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New device uses electrically assisted wind to fight fires

Photo, posted November 12, 2024, courtesy of the USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing carbon in buildings

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According to a new study by researchers at the University of California, Davis and Stanford University, construction materials used in buildings have the potential to lock away billions of tons of carbon dioxide.  The study, published in Science, shows that storing CO2 in buildings could be a major contributor to efforts to reduce greenhouse gas emissions.

Overall efforts in carbon sequestration take carbon dioxide – either as it’s being produced or once it’s already in the atmosphere – and store it away.  Storing it might involve injecting it into underground caverns or deep in the ocean.  Alternatively, storing it might involve converting it into a stable form using chemical reactions.  These various strategies involve both practical challenges and potential environmental risks.

The new study suggests that many materials that are already produced in large quantities have the potential to store carbon dioxide.  These include concrete, asphalt, plastics, wood, and brick.  More than 30 billion tons of these materials are produced worldwide every year.

Ways to accomplish carbon storage include adding biochar into concrete, using artificial rocks loaded with carbon as concrete and asphalt aggregates, plastic and asphalt binders based on biomass instead of petroleum, and including biomass fiber into bricks. 

The largest potential is using carbonated aggregates to make concrete.  Concrete is by far the world’s most popular building material with more than 20 billion tons being produced each year.

The feedstocks for these ways to store carbon in building materials are mostly low-value waste materials, so the economics of implementing these carbon sequestering strategies are likely to be quite favorable.

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Storing Carbon in Buildings Could Help Address Climate Change

Photo, posted October 19, 2022, courtesy of Alexandre Prevot via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ecofriendly Glass

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Glass has been used for thousands of years to make everything from windows to bottles to microscope slides.  For all that time, most glass has been in the form of soda lime silicate glass, which is made by melting quartz sand with carbon-based ingredients – soda ash and limestone – at high melting temperatures of about 2600 degrees Fahrenheit.

The process results in substantial carbon emissions.  Worldwide, glass manufacturing produces over 86 million tons of carbon dioxide per year.  Most of that comes from burning fuel to reach the high temperatures needed to make the glass, but about a quarter of it comes from the decomposition of the carbon-based materials used.

Researchers at Penn State University have developed an entirely new type of glass that represents an alternative to soda lime glass.  The glass – that they call LionGlass – eliminates the use of carbonate batch materials and has a melting temperature 700 degrees lower than traditional glass.   The new material has the potential to cut the carbon footprint of glass manufacturing in half.  It is also 10 times more crack-resistant than ordinary glass, which would enable light weighting of glass products, lowering the emissions associated with transporting glass and glass products.

Recently, Penn state has entered into a partnership with the Italian company Bormioli, one of the world’s leading glass manufacturers that specializes in high-end packaging for fragrances, cosmetics, and tableware.  By focusing on a smaller, high-end market, the focus can be on fine-tuning the glass and determining the feasibility of scaling it up further for other uses.

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Ecofriendly glass invented at Penn State secures partner for product development

Photo, posted December 26, 2005, courtesy of Lachlan Hardy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Eliminating plastic shipping pillows

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Anyone who gets packages from Amazon is familiar with the plastic air pillows used to keep products safe in transit.  Amazon uses almost 15 billion of them a year in North America.

Environmentalists have been urging Amazon and other vendors to cut down on the use of plastic packaging. The air-filled plastic pillows are made from plastic film, which is the most common form of plastic litter found in the sea and in seabeds along the shore.  Plastic film can be deadly to wildlife such as sea turtles and sea birds.  Plastic film generally can’t be composted or recycled either.

Recently, Amazon announced that it will replace its plastic pillows with recycled paper filler in all its North American markets – the United States, Canada, and Mexico – which together account for more than 70% of the retailer’s global sales.  It is already making the switch in a big way and is working towards fully removing the plastic materials by the end of the year.

Replacing plastic packaging with paper is a definite improvement.  Paper is recyclable and biodegradable.  It isn’t perfect:  if it ends up in landfills, it can contribute to methane pollution as it biodegrades.  But, on the other hand, paper packaging is more likely to be recycled.

Stemming the tide of plastic waste is an ongoing effort by environmental and consumer groups.  There is pending legislation in New York that aims to reduce the use of plastic packaging by 50% over 12 years by requiring manufacturers to either replace it or pay fees.  The bill cleared the State Senate but has not come up to a vote in the Assembly.  Similar legislation has already been passed in California, Oregon, Maine, and Colorado.

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Amazon Says It Will Stop Using Puffy Plastic Shipping Pillows

Photo, posted November 20, 2018, courtesy of Todd Van Hoosear via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Marine carbon dioxide removal

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About 30% of the carbon dioxide emitted by human activity is absorbed by the oceans.  As a result, they are getting warmer and more acidic, and the currents that help shape global weather are shifting.  To try to reduce global warming, people want to be able to store even more carbon dioxide in the oceans without the negative effects of doing so.

There are multiple efforts across the globe to achieve effective marine carbon dioxide removal.  Some are based on sinking carbon-rich materials to the bottom of the sea.  This is the marine equivalent of capturing CO2 from the air and storing it underground.  Other efforts involve increasing the alkalinity of the ocean, which increases its ability to chemically react with carbon dioxide as well as lowers its acidity, which is desirable in many ways.

Running Tide, a U.S.-based company, has been dumping thousands of tons of wood-industry waste 190 miles off the coast of Iceland.  The company has also been experimenting with dumping algae and kelp and sinking it deep below the ocean.  Such materials on land either get burned or decay, in both cases releasing CO2 into the atmosphere.  On the deep-sea bottom, the carbon is trapped.

Other efforts involve pumping seawater through electrodialysis filter systems to remove excess acidity or adding alkaline rocks to increase water alkalinity.

All of these efforts are a form of geoengineering, and like proposed ideas to cool the atmosphere, pose potential risks.  There is no silver bullet to solve the climate crisis.  It will take a combination of many solutions to address the issue of excess carbon dioxide in the atmosphere.  Marine carbon dioxide removal is one of the solutions that may play a role.

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Scientists Are Trying to Coax the Ocean to Absorb More CO2

Photo, posted February 22, 2018, courtesy of Bobbie Halchishak/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biodegradable microplastics

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Ordinary plastics are not biodegradable, but they are also not indestructible.  Plastics in the environment can break down into tiny fragments – microplastics – and those, unfortunately, are nearly indestructible.  Microplastics have been documented in the oceans and in soil virtually everywhere on Earth including remote frozen wastelands and on top of high mountains.  More recently, they have been found in our own arteries, lungs, and even in placentas.  Microplastic pollution is a very serious problem.

There is considerable ongoing effort to develop biodegradable plastics from non-petroleum sources.  There has been progress but it has not necessarily been aimed at creating bioplastics that do not create microplastic when they break down.

Researchers at the University of California San Diego have developed algae-based polymers that they have shown to degrade when composted.  Recently, in work published in the journal Nature Scientific Reports, they have shown that even fine microparticles of their bioplastic are digested by microbes when placed in a compost.  What remains are the starting plant materials from which the plastic was made.  Products made from this sort of plastic would not only be sustainable beyond their useful lifetime but would also not represent a potential danger to human life.

Creating this eco-friendly alternative to petroleum-based plastic is only the first step toward creating a viable replacement for existing plastics.  It is necessary to be able to use the new material on existing manufacturing equipment and for it to have the same mechanical and thermal properties as the materials it is replacing.  But the researchers are optimistic that this could be a potential solution to an increasingly serious problem.

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Say Hello to Biodegradable Microplastics

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ending plastic separation anxiety

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Petroleum-based plastics are one of the biggest environmental problems we face.  They mostly end up in landfills – or worse, in the oceans and elsewhere in the environment – and they basically don’t decompose over time.  Bio-based plastics were invented to help solve the plastic waste crisis.  These materials do break down in the environment providing a potential solution to the problem.  But it turns out that they can actually make plastic waste management even more challenging.

The problem is that bioplastics look and feel so similar to conventional plastics that they get mixed in with the petroleum-based plastics rather than ending up in composters, where they can break down as designed.

Mixtures of conventional and bioplastics end up in recycling streams where they get shredded and melted down, resulting in materials that are of very poor quality for making functional products.  The only solution is to try to separate the different plastics at recycling facilities, which is difficult and expensive to do.

Scientists at Lawrence Berkeley National Laboratory, the Joint BioEnergy Institute, and the incubator company X have invented a simple “one pot” process to break down mixtures of different types of plastic using naturally derived salt solutions and specialized microbes and then produce a new type of biodegradable polymer that can be made into fresh commodity products.

The team is experimenting with various catalysts to find the optimum way to break down polymers at the lowest cost and are modeling how their processes can work at the large scales of real-world recycling facilities. Chemical recycling of plastics is a hot topic but has been difficult to make happen economically at the commercial scale.

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Putting an End to Plastic Separation Anxiety

Photo, posted November 28, 2016, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Food and the climate crisis

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Agriculture is a major part of the climate problem and remains one of the hardest human activities to decarbonize.  It’s responsible for approximately 25% of global greenhouse gas emissions. 

Many experts contend that alternative food sources – like insect farming and seaweed aquaculture – are part of the solution.  Additionally, expanding production of climate resilient food crops, including quinoa, kernza, amaranth, and millet, likely also have a role to play. 

But according to a new study led by researchers from the University of California – Irvine, another solution to this problem may be to eliminate farms altogether.  In the study, which was recently published in the journal Nature Sustainability, the research team explored the potential for wide scale synthetic production of dietary fats through chemical and biological processes.  The materials needed for this method are the same as those used naturally by plants: hydrogen (in water) and carbon dioxide (in the air).   

The research team highlighted some of the potential benefits of farm-free food, including reduced water use, less pollution, localized food production, and less risk to food production from weather. 

Cookies, crackers, chips, and many other grocery products are made with palm oil, a dietary fat that continues to be a major driver of deforestation around the world.  However, it remains to be seen how consumers would react if the oil used to bake their cookies came from a food refinery up the road instead of a palm plantation in Indonesia.     

According to the researchers, depending on food refineries instead of tropical plantations for dietary fats could mitigate lots of climate-warming emissions while also protecting land and biodiversity.

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UC Irvine-led science team shows how to eat our way out of the climate crisis

Photo, posted July 15, 2008, courtesy of Quinn Dombrowski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electricity from chicken feathers

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The food industry generates enormous amounts of waste and by-products.  Each year, 40 million tons of chicken feathers are incinerated, causing adverse environmental effects.  Not only does it release large amounts of carbon dioxide but also produces toxic gases such as sulfur dioxide.

Researchers at ETH Zurich in Switzerland and Nanyang Technological University in Singapore have developed a way to put chicken feathers to good use by using them to make fuel cells more cost-effective and sustainable.

Using a simple and environmentally friendly process, they extract the keratin from the feathers.  Keratin is the protein that helps form hair, nails, the outer layer of skin, and feathers.  The extracted keratin is then converted into ultra-fine fibers known as amyloid fibrils.  The keratin fibrils are used in the membrane of a fuel cell.

Fuel cells generate clean energy from hydrogen and oxygen with only heat and water as byproducts.  At the heart of every fuel cell is a semipermeable membrane that allows protons to pass through but blocks electrons, thereby producing an electric current.  Fuel cells are the primary way hydrogen is used to directly generate electricity.  Hydrogen cars run on fuel cells.

Conventional fuel cells typically use membranes made from highly toxic chemicals.  The new ETH membranes essentially replace these toxic substances with biological keratin. 

The researchers are investigating how stable and durable their keratin membrane is and to improve it if necessary.  The team has already applied for a joint patent and is looking for partners and investors to further develop the technology and bring it to market.

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Generating clean electricity with chicken feathers

Photo, posted July 10, 2016, courtesy of Matthew Bellemare via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Moisture swing carbon capture

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As the world grapples with limiting the amount of carbon dioxide in the atmosphere, there is a growing need to capture the carbon dioxide that is emitted as well as preventing it from being emitted in the first place.  Carbon capture can be accomplished at the source of emissions (such as power plants) or it can be done by taking it out of the atmosphere.  The latter is called “direct air capture”.

It is not at all clear whether direct air capture can be accomplished on a scale that would really make a difference and at an acceptable cost either in dollars or energy expended.  But if it can be done that way, it would be a major tool in combatting climate change.

Direct air capture technology generally makes use of sorbent materials whose capacity to capture carbon dioxide and later release it is a function of temperature.  The process requires significant amounts of energy to release the carbon dioxide that has been captured. 

New research from Northwestern University makes use of the “moisture-swing” technique which uses materials whose ability to capture and release carbon dioxide depends on humidity rather than temperature.  While it takes some amount of energy to humidify the volume of air containing the sorbent material, it is very small compared to temperature-driven systems. 

There are many groups working with moisture-swing technology, but the Northwestern Group has identified a number of new sorbent materials with superior properties.

The fundamental questions of scalability and cost remain, but moisture-swing is a promising approach to direct air capture.  If carbon dioxide can be pulled out of the atmosphere in large volumes, it can be concentrated and stored or converted into useful products.

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Pulling carbon dioxide right out of the air

Photo, posted May 15, 2020, courtesy of James Watt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Paper Cups Are Not So Great | Earth Wise

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The environmental cost of plastic waste is a highly visible global issue.  The response has been a growing effort to replace plastic items with alternative materials.  One very visible change of this sort has been the replacement of plastic cups with paper cups at coffee shops.  But a new study at the University of Gothenburg in Sweden has found that this solution has problems of its own.

Researchers studied the effects of disposable cups in the environment on the larvae of the butterfly mosquito.  They placed disposable cups made from different materials in wet sediment and water for a few days and observed how the chemicals leached from the cups affected the growth of the larvae.  It turned out that all of the different kinds of cups had negative effects.  The concern is not specifically about mosquito larvae; it is the fact that more environmentally friendly drinking cups are still potentially harmful to living things.

Paper is neither fat nor water resistant, so paper cups need to be treated with a surface coating.  The most common coating is polylactide, which is a type of bioplastic.  It is generally considered to be biodegradable, but the study shows that it can still be toxic.  Bioplastics still contain many different chemicals and the potential toxicity of each of them is not well known.

The UN is trying to develop a binding agreement by the world’s countries to end the spread of plastics in society and nature.  For such an agreement to be effective, the plastics industry will need to clearly report what chemicals all products contain, including such mostly invisible products as the coating on paper drinking cups.

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Paper cups are just as toxic as plastic cups

Photo, posted October 23, 2016, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recycling Solar Panels | Earth Wise

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Solar panels generally have a useful life of around 20 to 25 years.  The great majority of deployed panels have been installed fairly recently, so they have a long way to go.  But the growth in solar technology dates back to the 1990s, so there are growing number of panels that have already or are shortly coming to their end-of-life.

Today, roughly 90% of solar panels that have lost their efficiency due to age, or that are defective, end up in landfills because recycling them is too expensive.  Nevertheless, solar panels contain valuable materials, including silver, copper, and crystalline silicon, as well as lower-value aluminum and glass. 

The rapid growth of solar technology means that in the coming years, large numbers of retired solar panels will enter the waste stream.  The area covered by solar panels that are due to be retired by 2030 in the U.S. alone would cover about 3,000 football fields.  Clearly, more cost-effective recycling methods are sorely needed.

Engineers at the University of New South Wales in Sydney Australia have developed a new, more effective way of recycling solar panels that can recover silver at high efficiency.  The panel frames and glass are removed leaving just the solar cells themselves.  The cells are then crushed and sieved in a vibration container that effectively separates 99% of the materials contained in them.

Silver is the most valuable material contained in solar cells.  The Australian researchers estimate that between 5 and 10 thousand tons of silver could potentially be recycled from retired solar panels by the year 2050.  But even the other materials contained in solar panels are well worth recovering if it can be done cost-effectively.

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New environmentally friendly solar panel recycling process helps recover valuable silver

Photo, posted November 22, 2008, courtesy of Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Concrete And Carbon | Earth Wise

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After water, concrete is the world’s second most consumed material.  It is the cornerstone of modern infrastructure.  Its production accounts for 8% of global carbon dioxide emissions.  The carbon dioxide is a result of chemical reactions in its manufacture and from the energy required to fuel the reactions.

About half of the emissions associated with concrete come from burning fossil fuels to heat up the mixture of limestone and clay that ultimately becomes ordinary Portland cement.  These emissions could eventually be eliminated by using renewable-generated electricity to provide the necessary heat.  However, the other half of the emissions is inherent in the chemical process.

When the minerals are heated to temperatures above 2500 degrees Fahrenheit, a chemical reaction occurs producing a substance called clinker (which is mostly calcium silicates) and carbon dioxide.  The carbon dioxide escapes into the air.

Portland cement is then mixed with water, sand, and gravel to produce concrete.  The concrete is somewhat alkaline and naturally absorbs carbon dioxide albeit slowly.  Over time, these reactions weaken the concrete and corrode reinforcing rebar.

Researchers at MIT have discovered that the simple addition of sodium bicarbonate (aka baking soda) to the concrete mixture accelerates the early-stage mineralization of carbon dioxide, enough to make a real dent in concrete’s carbon footprint.  In addition, the resulting concrete sets much more quickly.  It forms a new composite phase that doubles the mechanical performance of early-stage concrete.

The goal is to provide much greener, and possibly even carbon-negative construction materials, turning concrete from being a problem to part of a solution.

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New additives could turn concrete into an effective carbon sink

Photo, posted April 4, 2009, courtesy of PSNH via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Cars Getting Cheaper | Earth Wise

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A sticking point for buying electric cars has always been that they are typically more expensive than equivalent gasoline-powered cars.  But increasing competition, government incentives, and falling prices for lithium and other battery materials is changing the equation.  In fact, the tipping point when electric cars are as cheap or even cheaper than internal combustion cars is likely to happen this year for many cars and, in fact, has already happened for some.

Battery production is ramping up for Tesla, General Motors, Ford, and others, creating cost savings from mass production. Companies manufacturing batteries in the United States are receiving government subsidies as part of a drive to establish a domestic supply chain and reduce dependence on China.  Before anyone cries foul, it should be noted that globally, oil companies received a trillion dollars in subsidies last year.  The Inflation Reduction Act is making it cheaper for automakers to build electric cars (provided they do it in the United States using US materials) and cheaper for consumers to buy them because of tax credits.

Multiple companies have lowered the price of their electric vehicles in recent months, including both the Tesla Model 3 and Model Y, which are the best-selling electric cars in the United States. GM’s electric Equinox crossover will start at about $30,000, which is still about $3,400 more than the gas-powered version.  But once the electric vehicle tax credit is figured in, it will actually be cheaper.

Electric cars are already cheaper to own and operate because of the much lower cost of powering with electricity instead of gas as well as the greatly reduced maintenance costs for the vehicles.  Once the purchase price of these cars is less than that of gas-powered cars, the economics becomes a no-brainer.

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Electric Vehicles Could Match Gasoline Cars on Price This Year

Photo, posted May 11, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Self-Deicing Roads | Earth Wise

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Driving on snowy or icy roads can be pretty dangerous.  That is why roads are salted or coated with sand to provide traction in icy weather.  But excessive use of these substances is bad for the environment and sometimes a storm will blow in before the roads can be coated.

In a paper published in the American Chemical Society Journal ACS Omega, researchers in China describe a method of adding microcapsules filled with a chloride-free salt mixture to the asphalt with which roads are paved.  The idea is to provide the road itself with long-term snow melting capabilities.

The researchers prepared a sodium-acetate salt and combined it with a surfactant, silicon dioxide, sodium bicarbonate, and blast furnace slag, which is a waste product from power plants.  The substances were reduced to a fine powder and then coated with a polymer solution to form tiny microcapsules.  The microcapsules were then used to replace some of the standard mineral filler in asphalt.

Lab experiments showed that the special additive lowered the freezing point of water on the asphalt to -6 degrees Fahrenheit.   The researchers estimated that a 2-inch-thick layer of the anti-icing asphalt would be effective at melting snow for seven or eight years.  A real-world pilot test of the coating on a highway offramp showed that it melted snow that fell on the road whereas an uncoated road required snow removal operations.

According to the researchers, given the cost of materials used for the coating and its potential useful lifetime, it could be a practical and economic enhancement for wintertime snow and ice removal.  Maybe we’ll someday have roads that can fairly often deice themselves. 

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Keeping drivers safe with a road that can melt snow, ice on its own

Photo, posted April 8, 2007, courtesy of the Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fertilizing The Ocean | Earth Wise

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There are a variety of schemes for removing carbon dioxide from the atmosphere.  Some require advanced and generally not-very-well developed technology.  Others, such as planting vast numbers of trees, are nature-based but are daunting with respect to the scale to which they need to take place in order to be truly effective.

Researchers at the Pacific Northwest National Laboratory in Richland, Washington have been examining the scientific evidence for seeding the oceans with iron-rich engineered fertilizer in order to feed phytoplankton.  Phytoplankton are microscopic plants that are a key part of the ocean ecosystem.

Phytoplankton take up carbon dioxide as they grow.  In nature, nutrients from the land end up in the ocean through rivers and from blowing dust.  These nutrients fertilize the plankton.  The idea is to augment these existing processes to increase the growth of phytoplankton.  As they eventually die, they sink deep into the ocean, taking the excess carbon with them.


The researchers argue that engineered nanoparticles could provide highly controlled nutrition that is specifically tuned for different ocean environments.  Surface coatings could help the particles attach to plankton.  Some could be engineered with light-absorbing properties, allowing plankton to consume and use more carbon dioxide.

Analysis of over 100 published studies showed that numerous non-toxic, abundant, and easy-to-create metal-oxygen materials could safely enhance plankton growth.  According to the researchers, the proposed fertilization would simply speed up a natural process that already sequesters carbon in a form that could remove it from the atmosphere for thousands of years.  They argue that given the current trends in the climate, time is of the essence for taking action.

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Fertilizing the Ocean to Store Carbon Dioxide

Photo, posted August 2, 2007, courtesy of Kevin McCarthy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Windows To Cool Buildings | Earth Wise

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About 15% of global energy consumption is for cooling buildings.  Because of this, there is an ever- growing need for technologies that can more efficiently cool buildings.   Researchers at Notre Dame University have used advanced computing technology and artificial intelligence to design a transparent window coating that is able to lower the temperature inside buildings without using any energy.

The idea is to create a coating that blocks the sun’s ultraviolet and near-infrared light, which are parts of the solar spectrum that otherwise pass through glass and help to heat an enclosed room.  Cooling needs can be reduced further if the coating can radiate heat from the surface of the window so it can pass through the atmosphere into space.  Designing a coating that does both of those things simultaneously while transmitting visible light is difficult.  Coatings should not interfere with the view out the window.

The Notre Dame researchers used advanced computer modeling to create a so-called transparent radiative cooler that meets these goals.  The coating consists of alternating layers of common materials like silicon dioxide, silicon nitride, and aluminum oxide or titanium dioxide on top of a glass base and topped with a film of polydimethylsiloxane.  The computing method was able to optimize this structure far faster and better than conventional design techniques.

The researchers say that in hot, dry cities, the coating could potentially reduce cooling energy consumption by 31% compared with conventional windows.  The same materials could be used in other applications, such as car and truck windows.  In addition, the quantum computing-enabled optimization method used for this work could be used to design other composite materials.

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Clear window coating could cool buildings without using energy

Photo, posted September 6, 2015, courtesy of Robert Otmn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon Storage In Harvested Wood | Earth Wise

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Trees are an exceedingly important carbon sink on our planet.  For this reason, deforestation is a major contributor to climate change.  But when trees are harvested for wood products like lumber, much of the carbon in that wood continues to be stored.  Even when a wood product is discarded at the end of its useful life, it can keep storing carbon.

Over 90% of new single-family homes in the U.S. are built with wood.  Each year, about 400,000 homes, apartment buildings, and other housing units are lost to floods and other natural disasters.  Others fall apart from decay or are torn down to be replaced with newer structures.  Given how much carbon is stored in houses, it is important to understand what the future trajectory of residential structures will be.

A new study by the USDA Forest Service published in the journal PLOS ONE looks at the future of harvested wood products in residential structures.  According to the study, wood products in these structures will continue to increase the country’s carbon storage for the next 50 years. 

Even after residential structures reach the end of their useful life and much of the materials end up in landfills (which is typical in this country), the wood products do not immediately release their carbon.  It may take decades for that to happen.

The study looked at various scenarios for future home construction.  Although housing starts are projected to decline in the future, residential housing and the need to maintain existing structures are projected to continue to increase carbon storage in wood products for the next several decades.

The role of trees as a carbon sink does not end when they are harvested for their wood.

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Carbon Storage in Harvested Wood Products

Photo, posted January 27, 2022, courtesy of Luke McKernan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar-Powered Desalination | Earth Wise

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About two-thirds of humanity is affected by water shortages.  In the developing world, many areas with water shortages also lack dependable sources of electricity.  Given this situation, there is widespread research on using solar heat to desalinate seawater.  To date, many approaches to this face problems with fouling of equipment with salt buildup.  Tackling this issue has proven to add complexity and expense to solar desalination techniques.

A team of researchers from MIT and China has recently developed a solution to the problem of salt accumulation that is more efficient than previous methods and is less expensive as well.

Previous attempts at solar desalination have relied on some sort of wick to draw saline water through the device.  These wicks are vulnerable to salt accumulation and are difficult to clean.  The MIT-Chinese team has developed a wick-free system instead.  It is a layered system with dark material at the top to absorb the sun’s heat, and then a thin layer of water that sits above a perforated layer of plastic material.  That layer sits atop a deep reservoir of salty water such as a tank or pond.  The researchers determined the optimal size for the holes in the perforated plastic.

The 2.5 millimeter holes are large enough to allow for convective circulation between the warmer upper layer of water above the perforated layer and the colder reservoir below.  That circulation naturally draws the salt from the thin layer above down into the much larger body of water below.

The system utilizes low-cost, easy to use materials.  The next step is to scale up the devices into a size that has practical applications.  According to the team, just a one-square-meter system could provide a family’s daily needs for drinking water.

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Solar-powered system offers a route to inexpensive desalination

Photo, posted February 13, 2017, courtesy of Jacob Vanderheyden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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